1. Field of the Invention
This invention relates to a process for producing an ink jet head, particularly to a process for producing a liquid jet recording head (ink jet recording head) having a discharging opening plate of the type, in which the direction of feeding liquid (ink) to the discharge energy generating member-corresponding portion in the liquid channel (ink pathway) and the discharge direction of the liquid from the discharge opening are different, as a part of the constitution.
2. Related Background Art
The Liquid jet recording head (ink jet recording head) applied to the liquid jet recording system (ink jet recording system) is generally equipped with a fine discharge opening for recording liquid (hereinafter also referred to as "orifice"), a liquid channel (ink pathway) and a liquid discharge energy-generating portion provided on a part of said liquid channel. In the prior art, as the method for preparing such a liquid jet recording head, for example, there has been known a method, in which a plate such as glass, metal, etc. is used, a fine groove is formed by working such as cutting, etching, etc. and then the plate having said groove formed thereon is bonded with another appropriate plate to form a liquid channel.
However, in the liquid jet recording head prepared according to such prior art method, the coarseness of the inner wall surface of the liquid channel formed by cutting may be too great or distortion may occur in the liquid channel due to the difference in etching rate, whereby there were problems such that it was difficult to obtain liquid channels with constant liquid channel resistance, and that variance might occurr in the recording liquid discharge characteristics of the liquid jet recording head after preparation. Also, defects and cracks in the plate wear liable to be formed during cutting, whereby there was also the problem that the production yield was not so good.
Further, in the case of etching, the production steps are many, whereby there was also a disadvantage that increase of the production cost was brought about.
On the other hand, as the problem common to the above-mentioned prior art methods, in plastering a grooved plate having liquid channel formed thereon with a substrate provided with a driving element such as a piezoelectric element or electricity-heat converter for generating the discharge energy to be utilized for discharging recording liquid, registration between these plates was difficult, whereby there was also the problem of lacking bulk productivity .
Also, a liquid jet recording head, generally under its use environment, is always in contact with a recording liquid (generally an ink solution composed mainly of water which is not neutral in most cases, or an ink solution composed mainly of an organic solvent). Therefore, while the structural material constituting the liquid jet recording head is desired to not be affected by the recording liquid, regarding its strength or on the contrary to not contain a harmful component which will lower recording liquid adaptability, in the prior art method as mentioned above, partially because of the restriction of the working method, etc., it has not necessarily been possible to choose a material suited for such objects.
As the technique for solving such problems of the prior art methods, the present inventors invented a process for producing a liquid jet recording head by use of an active energy ray curable material as the member for formation of the liquid channel wall as disclosed in Japanese Patent Laid-open Application No. 61-154947.
However, said method proved to be not necessarily satisfactory in manufacturing freely the liquid chamber, such as the size and the height of the liquid chamber connected to the liquid channel. Particularly, in a liquid jet recording head of the full-line type which performs discharging over the full paper width of recording paper with orifices and liquid channels communicated thereto arranged at high density, it is important to make the liquid chamber volume large in order to effect stable and uniform discharging of recording liquid, and it has been strongly desired to develop a production process suited for bulk production of a liquid jet recording head of such high density multi-orifice type.
In order to solve these problems, the present inventors invented a process which comprises, as a summary, laminating successively on a first substrate a solid layer for formation of at least one liquid channel, an active energy ray curable material layer to be utilized for formation of the wall of the liquid channel and a second substrate, then laminating a mask of said second substrate, irradiating an active energy ray from above said mask to cure at least the wall of liquid channel of the active energy ray curable material layer, and further removing the solid layer and the active energy ray curable material layer from between the two substrates as presented in U.S. Ser. No. 500,094, filed Mar. 21, 1990, U.S. Pat. No. 5,030,317 which is a continuation of U.S. Ser. No. 177,833, filed Mar. 24, 1988, abandoned and which is a continuation of U.S. Ser. No. 038,766, filed Apr. 15, 1987, abandoned.
However, in said process, because of having a mask laminated on said second substrate, due to the influence of diffraction of active energy ray or the oblique light component in the active energy ray in the process of passing through said second substrate, the edge portion of the pattern of the cured portion becomes indistinct, whereby the liquid channel, etc. of desired shape could not be obtained in some cases.
Further, in this process, an alignment device for registration between said second substrate and said mask is required.
Besides, in this process, when slippage occurs in registration in the alignment operation, the precision of liquid channel dimensions becomes worse. Also, there is such problem that for correct registration, a skilled technique and much time are required.
In the state of the art as described above, as the liquid jet recording head which performs recording by discharging liquid through discharge opening, various types have been known.
As broadly classified, there are the type in which the feeding direction of liquid to the portion where the energy to be utilized for discharging liquid from the discharge energy generating member in the liquid channel and the discharge direction from the discharge opening are substantially the same, and the type in which these directions differ by, for example, 70.degree..
As the production process of the latter type, for example, the process as described below is disclosed in Japanese Patent Laid-Open Application has been known.
First, as shown in FIG. 1A, on a substrate 1 provided with an energy generating member 2 for generating the energy to be utilized for discharging liquid, in order to provide energy acting chambers 18 and a liquid chamber 11 communicated commonly to the respective energy acting chambers according to the photolithographic method conventionally practiced, for example, a wall 16 with a predetermined shape is formed by use of a photosensitive material.
Next, as shown in FIG. 1B, the discharge opening plate 6 having discharge openings 8 for discharging liquid is bonded to the wall 16 with an adhesive 17 with registration so that the respective discharge openings may be arranged corresponding to the respective energy acting chambers, to give a liquid jet recording head as shown in the plan view in FIG. 1C.
However, according to the process as described above, since the step of bonding the discharge opening plate with an adhesive after formation of the energy acting portions and the wall for formation of the common chamber with a photosensitive material; the following problems sometimes occurred.
1) Into the liquid channel and the common liquid chamber formed on the substrate, through the preparation steps, garbage or dust, etc. are liable to be entrained and remain, whereby the yield is poor.
2) Setting of the kind and application conditions of the adhesive during bonding of the discharge opening plate was difficult, and in some cases, the discharge opening may be clogged with the adhesive, or the adhesive may flow into the liquid channel and the liquid chamber.
3) For obtaining well-balanced adhesion strength on the respective bonded surfaces of the wall formed by use of the photosensitive resin, the adhesive layer and the discharge opening plate, the kind of the adhesive employed is limited.
4) A flat plane characteristic is necessary for good adhesion of the bonded surface between the discharge opening plate and the wall on the substrate.